The surface-tension of pure mercury is so great that it is very difficult to keep it clean, for every kind of oil or grease spreads over it at once.
Thus, as the cult of a particular divinity spreads farther and farther, so the circle expands from which are drawn those who visit his sanctuary.
Some are black, very thin and curved like threads or hairs (trichites); often a group of these is seated on a small crystal of augite or magnetite and spreads outwards on all sides.
The mycelium spreads through the green parts of the plant, attacking the leaves, twigs and unripe grapes.
Rotting of the wood at the base of the trunk is also caused by Agaricus melleus, which spreads from root to root in the soil by means of its long purple-black, cord-like mycelial strands known as Rhizomorpha.
Among exotics the Australian saltbush spreads successfully over the worst alkali land.
In the northern part of the country it spreads into several side valleys, from one of which rises the extinct volcano Kilimanjaro, the highest mountain in Africa (19,321 ft.).
The largest tract of them is to be seen to the south of the Cantabrian chain; but another, of hardly inferior extent, flanks the Sierra de Guadarrama, and spreads out over the great plain from Madrid to Cceres.
The disease spreads from grape to grape, so that as a rule many of the grapes in a bunch are destroyed.
The underground mycelium in many cases spreads wider and wider each year, often in a circular manner, and the sporophores springing from it appear in the form of a ring - the so called fairy rings.